question stringlengths 37 38.8k | group_id stringlengths 2 6 | sentence_embeddings listlengths 768 768 |
|---|---|---|
<p>Anyone knows any R package/function to run a reaction norms model for the analysis of genotype × environment interactions? I don't know if shuch models could be performed using the lme4 or the MCMCglmm packages.</p> | g64409 | [
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<p>According to the info in the following locations:</p>
<ul>
<li><a href="http://en.wikipedia.org/wiki/Truncated_normal_distribution" rel="nofollow">http://en.wikipedia.org/wiki/Truncated_normal_distribution</a></li>
<li><a href="http://en.wikipedia.org/wiki/Truncated_distribution" rel="nofollow">http://en.wikipedia.... | g64410 | [
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<p>There was too much snow on the highways, so the mayor of the town sent snowplows to spread some chemicals on them. There is a standard of how much of one specific substance should be present in the compound that is used for spreading...
We measured how much of the substance was present in the compound in 30 differen... | g64411 | [
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<p>I would like to know if there are any rules to determine if Pearson's r correlation values are similar to Spearman's rho?</p>
<p>For example, if r = -.207 and rho = -.282, are these similar enough to just report r? </p> | g22523 | [
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<p>I have built a simple classification neural network with feed-forward and backpropagation and one hidden layer (code below) and I would like to explore the effect of changing:
- the learning rate
- the number of nodes in the hidden layer, and
- the order in which the training examples are presented.</p>
<p>I hav... | g64412 | [
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<p>I am working with regressions to understand the price creation of certain future contracts for commodities and try to explain it with other commodity pricese.
These future contracts have different time periods until they start with their delivery.
It is intuitive that a future contract with a long time to delivery e... | g22525 | [
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<p>I need references on tools for testing the validity of technical analysis indicators on stocks market.</p>
<p>The tools I want could be anything, the technical analysis indicators are a list of values built from some stocks market parameters, such as price and volume - from these newly built indicators, there are s... | g22526 | [
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<p>I need an explanation. For Cox regression, is it true that: </p>
<ul>
<li>an effect of one year of age is the same in 50-years old as in 70-years old?</li>
<li>an effect of one year of age is the same a year after the diagnosis as 5 years after the diagnosis. </li>
</ul>
<p>Thanks.</p> | g64413 | [
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<p>I have time series data recorded at multiple locations, stored in a matrix $Y$. I have fit a Vector Autoregressive Model to it which forecasts the data pretty well on a test set. However, if I plot the residuals there is definitely some time series structure left; ideally the residuals would look like noise. </p>... | g64414 | [
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<p>I generated some data according to a mixture of two lognormals:
$f(x) = p \cdot \mathcal LN(\mu_1, \sigma) + (1-p) \cdot \mathcal LN (\mu_2, \sigma)$.</p>
<p>given $p$ and $\sigma$, this is my code to find $\mu_1, \mu_2$ by MCMC with the
<code>mcmcPack</code> R Package:</p>
<p>the mixture density:</p>
<pre><code>... | g22529 | [
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<blockquote>
<p>Say there are two groups, each with n=500, with y=weight in pounds. The sample mean and sample standard deviation of weight are given:</p>
<p>Exercise(X=1): Mean=170, SD=20<br>
Non-Exercise(X=0): Mean=190, SD=20</p>
<p>a. Would the regression equation be: y=b0+b1x, so y=190-20x?</p>
<... | g64415 | [
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<p>I am trying to understand under what circumstances the log likelihood function of a point process concave. Assume that the process can be defined by a conditional intensity function and that the log likelihood function exists. Is there a general theory or good reference for understanding when the log likelihood fu... | g64416 | [
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<p>I have about 10 variables about products. I need to rank order the products by quality. Now, the quality is very subjective thing, so I got all 300 products ranked by domain experts.</p>
<p>Now I have 10 variables, and ranking assigned by an expert. About 1% of products should be excelent, about 10% should be very ... | g49353 | [
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<p>I'm doing some failure time analyses where I'm trying to determine a failure rate function, and use the delta method to determine a confidence interval for the time when 25, 50%, etc. failure occurs. I'm used to doing this with a slope parameter, but what about when you are given intercept and scale parameters inste... | g64417 | [
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<p>Are there well known formulas for the order statistics of certain random distributions? Particularly the first and last order statistics of a normal
random variable, but a more general answer would also be appreciated.</p>
<p><strong>Edit:</strong> To clarify, I am looking for approximating formulas that can be mo... | g64418 | [
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<p>I know there are similar posts, and I've read a few of them already, but none of them give explanations that I actually understand. I'm completely new to statistics and am finding it more difficult that there seems to be many versions of tests suggested when comparing 2 poisson distributions. The worst part, is I'm ... | g64419 | [
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<p>If I have built a certain construct measuring scale aggregating items from different previously validated scales, I am unsure what strategy would be best to validate my resulting scale. I intend to use PCA to reduce the dimensionality of the scale and use it for cluster analysis. Should I randomly devide my sample a... | g22536 | [
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<p>I'm faced with a practical problem of solving for a 1-D function which has noise, so find myself in the territory of stochastic approximation (and I am well out of my comfort zone here!). I know there is some literature on the problem, but I've yet to find anything on the particular case I have in mind, where the n... | g22537 | [
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<p>I've just received some survey data and I found that the results are highly positively skewed. Most of the questions were answered on a five-point Likert scale, and the mean values of many questions are around 4.3, with standard deviations of 0.5 or 0.6.</p>
<p>Another problem is that in the questionnaire I include... | g64420 | [
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<p>I'm using the <a href="http://cran.r-project.org/web/packages/quantreg/index.html">quantreg</a> package to make a regression model using the 99th percentile of my values in a data set. Based on advice from a previous stackoverflow <a href="http://stackoverflow.com/questions/4594370/advice-on-calculating-a-function-t... | g64421 | [
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<p>I have a simple question about the GARCH model.</p>
<p>We know that the $\alpha$ and $\beta$ parameters of the models are fitted for the local volatility of each time $t$ as follows:</p>
<p>$$\sigma_t^2= \alpha_0 + \sum_{i=1}^q \alpha_i \varepsilon_{t-i} + \sum_{i=1}^p \beta_i \sigma_{t-i}^2$$</p>
<p>with $\varep... | g64422 | [
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<p>I'm using PCA to reduce dimensionality before I feed the data into a classifier. My bootstrap/cross-validation has shown a significant reduction in test error as a result of applying PCA and keeping the PCs whose standard deviation is a fraction (say, 0.05) of the standard deviation of the first PC. My features are ... | g22539 | [
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<p><a href="http://www.jstatsoft.org/v45" rel="nofollow">Volume 45</a> of the <em>Journal of Statistical Software</em> contains articles about packages that deal with imputation of missing data, one of which is the <a href="http://cran.r-project.org/web/packages/mi/index.html" rel="nofollow">mi</a> package. In the PDF ... | g64423 | [
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<p>I am working on a problem that its difficult part is to invert a covariance matrix (in R). I could not use usual approches like SVD and Chol. Then, I decided to use a Discrete Fourier Transform (DFT) approach. But I couldn't understand how to apply the method, especially in R. So, your comments and possible examples... | g22541 | [
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<p>I am making some marketing research for a new ready to drink product.</p>
<p>I want to measure consumers expected quality and experienced quality. Therefore consumers are to answer questions abut the expected quality before and after they have tasted the product to see whether the experienced quality lives up to th... | g64424 | [
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<p>I have used the following Likert scale for a series of questions in a survey:</p>
<ul>
<li>$0=$ Not Important </li>
<li>$1=$ Slightly Important </li>
<li>$2=$ Moderately Important </li>
<li>$3=$ Very Important </li>
<li>$4=$ Extremely Important</li>
</ul>
<p>As I understand it, this is a 5-point Likert scale. (Uns... | g46214 | [
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<p>I need to estimate the statistical power of a multilevel test in order to estimate the sample size needed. The levels of the model include country, center and individual person. I will be measuring the difference in treatment effect between two treatments.</p>
<p>I found the following R code on <a href="http://www.... | g64425 | [
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<p>I am trying to run a Generalized Linear Mixed Model on some data. What I am trying to do is use distances from habitat features to predict a distance between 2 animal locations. I ran a PCA on the habitat variables, and selected 5 Principal Components to include. The data is badly uneven and has pseudoreplication as... | g10596 | [
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<p>Have, let's say, the following data:</p>
<blockquote>
<p>[1] 8232302 684531 116857 89724 82267 75988 63871 23718 1696 436 439 >[12] 248 235</p>
</blockquote>
<p>Want a simple way to fit this (and several other datasets) to a Pareto distribution. Ideally it would output the matching the... | g64426 | [
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<p>Having a random variable $X$ with a given density function $f_{X} : [a .. b] \rightarrow\mathcal{R}_{+}$ and a point c, $c \in [a .. b]$ I am curious if the following problem has a solution:</p>
<p>Find two independent random variables $X_1$ and $X_2$ such that $X = X_1 + X_2$ with the additional property that the ... | g42525 | [
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<p>If $X$ is an exponential random variable with parameter $\lambda$ and we have that $[x]$ is defined as the largest integer $n$ such that $n \leq x$. </p>
<p>If $Y$ is defined as $$Y = \left[ X\over a \right]$$ where $a>0$ then how would you find the probability mass function of $Y$?</p> | g64427 | [
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-0.015755407512187958,
0.0469917356967926,
... |
<p>In my class, we are covering tests of hypothesis about the mean. Two sample T-tests can be either paired or unpaired. When encountering problem descriptions, how can one determine from which study design was the sample ascertained?</p> | g22546 | [
0.02842162735760212,
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0.009556670673191547,
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0.029... |
<p>How does one compare means between two groups that contain repeated measures. For instance:</p>
<p>Group 1 = has mutation A</p>
<p>Group 2 = has mutation B</p>
<p>Dependent variable = blood pressure (continuous variable)</p>
<p>Group 1 has 140 data points and 52 participants. Group B has 120 data points and 30 p... | g22547 | [
-0.006342822220176458,
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... |
<p>I'm currently trying to make some simple models of client lifetime value. I'm using the following simplified formula for some survival analysis on client values</p>
<pre><code>fit1 <- coxph( Surv(Start, Start + Time, Death) ~ Service, survData)
</code></pre>
<p>I can call <code>basehaz</code> on <code>fit1</cod... | g22549 | [
0.03195988014340401,
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<p>I want to conduct a PCA in SPSS. One assumption for PCA is that there are no significant outliers. How can I identify outliers in SPSS? </p> | g22550 | [
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<p>Recently one of my friends asked me this deceivingly simple question:</p>
<blockquote>
<p>I have a midterm with a predetermined list of 15 possible questions. Out of the 15 questions only 7 will actually appear on the test. Out of the 7 that appear on the test I will only have to answer 5. How many answers should... | g64428 | [
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<p>I want to test a hazard ratio I estimated against some previously described. A Wald test seemed appropriate, utilizing the approximate normal distribution of the log hazard ratio.</p>
<p>I therefore calculated the difference between my estimated and the proposed true log hazard ratio, divided it by the estimated st... | g64429 | [
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<p>Suppose there exists a sequence of $n$ numbers with two possible instantiations: </p>
<ol>
<li>The sequence contains all zeros; </li>
<li>$n-1$ of the numbers are zeros, and one is a zero-mean Gaussian random variable $y_t\sim\mathcal{N}(0,\sigma^2)$ where $t$ denotes
the location of the Gaussian in the sequence... | g10600 | [
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<p>I am studying classification using linear regression . Now, I want to map it in Bayesian regression. Let talk about binary classification using linear regression again. Assume that I have a set $X=${$x_1,x_2...x_n$} and binary lable $y$={$0,1$}. Binary classification using linear regression task can embedded in to m... | g64430 | [
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<p>This may be a silly question, but I can't find a concise answer. I've been studying Convergence of Random Variables in Wasserman's <strong>All of Statistics</strong>, which starts out by explaining: </p>
<p>$X_n$ is a sequence of random variables: $\{X_1, X_2, ... X_n\}.$</p>
<p>It then goes on to define the <stro... | g64431 | [
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<p>I have a set of data train that includes texts and associated labels: true or false.
The label distribution is: 97% false, 3% true.</p>
<p>I wish to detect the true labels, using Naïve Bayesian.</p>
<p>Should I train my Naïve Bayesian classifier with all train data (97% false, 3% true), or should I “normalize” it ... | g64432 | [
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<p>I'm learning about GPs in hopes that it'll be the tool I need to deal with the common scenario I encounter where I have a continuous predictor variable whose effect might not be linear. I think I understand the simple GP whereby the parameters specifying the covariance matrix creation function, eta, rho, and sigma, ... | g10601 | [
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<p>I am doing an experiment about the interpretation of a message with or without emoticons and in relationship with the individual TOM (low or high). It will be a within subject design where the same participant interprets the message under two conditions (with or without emoticons) on a scale form one to seven ( one:... | g22555 | [
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<p>I need to do forecasting of weekly sales using Holt-Winters technique. My data have max 92 weeks of information. I'm planning to consider 72 weeks of data for training & 20 weeks of data for validation & I have only available s/w to do the forecast is R. I'm preparing my training & validation data set us... | g64433 | [
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<p>I've got the following sets of data (x and y scales on each chart are identical):</p>
<p><img src="http://i.stack.imgur.com/jVe2Q.png" alt="enter image description here"></p>
<p>The eye picks out an upward-sloping floor trendline on each chart that runs upward from left to right, hugging the bottom of the bulk of ... | g22557 | [
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... |
<p>I wrote PHP-code that gets me samples of a (truncated) exponential distribution between 0 and 1 with mean 1 ($X\sim \mathrm{Exp}(1)$). </p>
<p>I'm trying to use acceptance-rejection method: I don't know if I get it right, but basically I use one sample of a $\mathrm{Uniform}(0,1)$ distribution to get the x-axis and... | g20378 | [
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<p>This is a homework question. I think I have the correct answer, but I am not sure. Also, the wording sounds very awkward. Is there a better way to show this (or better way to word this)?</p>
<p>Let $X_1,\ldots,X_n$ be a random sample from $f_\theta(x)$, where $f_\theta(x)$ is a continuous density with support $[\th... | g22560 | [
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<p>I was wondering about about the following problem:</p>
<p>I have a set of $N=10^5$ observations with dimensionality $D=2$, and I would like to reduce it to a set of size with $M=10^3$, or some other $(M \ll N)$, while retaining most of the information contained in it. I assume M is fixed in advance. (The observatio... | g64434 | [
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<p>I have three datasets as follows:</p>
<ul>
<li>Dataset A can have a maximum score of 30. (Individual scores can be from 1 to 30)</li>
<li>Dataset B can have a maximum score of 45. (Individual scores can be from 1 to 45)</li>
<li>Dataset C can have a maximum score of 25. (Individual scores can be from 1 to 25)</li>
... | g64435 | [
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<p>I'm making a video about dice, so I went online and bought some loaded dice. The ones I bought are "shaved dice", or "flats", these ones in specific: <a href="http://rads.stackoverflow.com/amzn/click/B008QDJ4RI" rel="nofollow">http://www.amazon.com/gp/product/B008QDJ4RI/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1</... | g64436 | [
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<p>I want to analyze results from a computer simulation in which I will vary two factors: (1) fan location, and (2) fan flow rate. After the simulation, I will query the results for gas concentrations on a reference plane located 1" above the perforated tank lid. At the end of five minutes of fan operation, I will c... | g64437 | [
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<p>Given two experimental runs, each with an experimental & a control group, I would like to test for a statistically significant difference between the first and second experimental group (using Welch's t-test). Because of inter-experimental variability, this requires <strong>normalization of the values in the exp... | g64438 | [
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<p>I have one interval variable on a 1-25 point interval scale, i.e. placement test scores where 25 is the highest competence score (data not normally distributed), and six different ordinal variables on a 1-7 likert scale (where 7 is the highest score) in my data set. There are 12 participants (12 interval test score... | g28849 | [
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<p>I am conducting a study on a pool of data which consisted of 200 items. I am planning to use rating scales to see how these items relate to a concept (e.g. "how are the next items related to the attractiveness of a product?") and the rating scales ranges from 1-very closely related, to 7-not related at all.</p>
<p>... | g64439 | [
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0.01154807023704052,
0.047298818826675415,
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<p>I'm trying to do a multiple linear regression model to correlate a dependent $Y$ variable (normally distributed) against a set of 642 variables. These 642 variables codify for the presence or absence of a particular chemical group in a molecule, therefore they can assume only <code>1</code> or <code>0</code> as valu... | g64440 | [
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<p>I'm dealing with 3D data that are the trajectory of a point over time. I would like to have an indication of how much it is "spread" in space and I thought about using the volume of the 95% confidence ellipsoid as they do for stabilometric measures in 2D with the displacement of the <a href="http://en.wikipedia.org/... | g22564 | [
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<p>I can see why you might not use a more powerful method, such as the Hochberg method, over the Bonferroni correction, as they may have extra assumptions, such as the independence of hypotheses in this case, but I don't understand why you would ever use the Bonferroni correction over Holm's sequentially rejective modi... | g64441 | [
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<p>I am using <code>auto.arima</code> for forecasting. I have more than one categorical variables having more than one level. </p>
<p>My questions are :</p>
<ol>
<li><p>Do I need to do dummy coding ?</p></li>
<li><p>If I do dummy coding with my categorical variables, this will result into 20 variables. Is it good to ... | g22566 | [
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<p>I wish to test my time series data for volatility clustering, i.e. conditional heteroskedasticity.</p>
<p>So far, I have used the ACF test on the squared and absolute returns of my data, as well as the Ljung-Box test on the squared data (i.e. McLeod.Li.test).</p>
<p>In a recent paper (<a href="http://papers.ssrn.c... | g22567 | [
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0.02122... |
<p>I am reading a paper about the Dirichlet process and image segmentation.
(<a href="http://dl.acm.org/citation.cfm?id=2404806" rel="nofollow">http://dl.acm.org/citation.cfm?id=2404806</a>)</p>
<p>How is (3) below derived? Do any articles or posts explain image segmentation and the Dirichlet process?</p>
<blockquote... | g64442 | [
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0.... |
<p>I want to know if you can helpme
I have a binaray response yt take values 1,0 and a covariate Xt continua and I have to estimate the parameters of the model using maximun likelihood method</p>
<p>yt=b1+b2*yt-1+b3*Xt-1</p>
<p>any idea or help can be done for either R stata eview or sas </p>
<p>thanks for help</p> | g64443 | [
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<p>In "The Elements of Statistical Learning" (2nd ed), p63, the authors give the following two formulations of the ridge regression problem:</p>
<p>$$ \hat{\beta}^{ridge} = \underset{\beta}{\operatorname{argmin}} \left\{ \sum_{i=1}^N(y_i-\beta_0-\sum_{j=1}^p x_{ij} \beta_j)^2 + \lambda \sum_{j=1}^p \beta_j^2 \right\} ... | g64444 | [
0.030477002263069153,
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0.02417578548192978,
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0.05775340646505356,
0.05526558309793472,
0.0538... |
<p>I was wondering if Markov Clustering is what I really am looking for or not.</p>
<p>Basically I have a N node graph in which every node is directly connected with one another. However, all the edges are weighted from 0 to 1. </p>
<p>Will using MCL produce a useful cluster, or should I be looking somewhere else?</p... | g22572 | [
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0.... |
<p>I want to model the probability of a binary variable x given some predictor, d. It needs two parameters:</p>
<ul>
<li>One parameter that sets the "break point", at which p(x=1 | d) = 0.5.</li>
<li>One parameter that sets the "softness", i.e. how abruptly the probability changes around the break point.</li>
</ul>
... | g64445 | [
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0.028774326667189598,
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0.0047438787296414375,
0.021219326183199883,
0.07895170897245407,
-0... |
<p>Is it possible to classify the points inside a square ? i.e. if $a \le x \le b$ and $c \le y \le d$ then label is $+1$ otherwise $0$.</p>
<p>Is that possible using SVMs for example ?</p>
<p>Thanks,
Zach</p> | g64446 | [
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0.0... |
<p>I have been reading about errors-in-variables (also called regression dilution and attenuation) but I've found it hard to decide whether it is appropriate for my setting. </p>
<p>I want to calculate correlations, and I've read that due to measurement errors, the computed correlations will be underestimated. </p>
<... | g7393 | [
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0.009... |
<p>Somebody could explain me why the estimated coefficients of a multiple regression through GLS seem not to pass through the majority of observations?</p>
<p>Here is a example:</p>
<pre><code>require(nlme)
set.seed(1)
df=data.frame(y=rank(rnorm(50,0)),x1=rank(y+rnorm(50,0))/2,x2=rank(y*2+rnorm(50,0)),x3=rank(rnorm(5... | g22574 | [
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0.061052992939949036,
... |
<p>I found this for a week, but I still cannot find anything about it.</p>
<p><strong>In a regression, Y = a + b * X + controls +e</strong></p>
<p>If we add dummy D=1 for group A and 0 for others, it becomes
<strong>Y = a + b*X + c*D + f*X*D + controls + e</strong></p>
<p>The impact of X on Y for group A is (b+f), ... | g22575 | [
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0.017419159412384033,
0.060963913798332214,
0.05485236272215843,
0.05... |
<p>I created a logistic regression model to predict, for a people off work due
to illness, the probability each of them would go back to work in the
upcoming month. (Based on a number of factors like age, how long they've
been off, why they are off work, etc.)</p>
<p>Comparing the output of the model across time, I ca... | g64447 | [
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0.010533459484577179,
0.06987419724464417,
-0... |
<p>I have a survey dataset. We asked numerous questions to get at one point: "how integrated are you in your community?" I want to run factor analysis to get a "community integration" factor.</p>
<p>Should I
(1) run FA on all the survey variables, and use the factor that looks like the "community integration" factor
O... | g64448 | [
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0... |
<p>This problem appear in an exam put by Chris Sims (3):
<a href="http://sims.princeton.edu/yftp/emet04/ConfidenceCredibilityEx.pdf" rel="nofollow">http://sims.princeton.edu/yftp/emet04/ConfidenceCredibilityEx.pdf</a></p>
<hr>
<p>Suppose the following model: $y=\beta_1 +\beta_2 X_2+\beta_1 X_3 +\epsilon$ with $\epsil... | g64449 | [
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0.08503598719835281,
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... |
<p>I'm currently working on the data which has 90% 0s in response variable. Based on my research, it seems zero inflated models could be a solution to this. However, while I was reading related documents, it seems the basic idea of two part model( hurdel) is </p>
<p>$ E[Y|X] = P(Y>0|X) E[Y|X,Y>0]$</p>
<p>Th... | g64450 | [
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0.05752066522836685,
0.0026685490738600492,
0.09080345928668976,
... |
<p>I want to compare car accident deaths in two groups of people aged 18-24 (lets use this as the reference) and 24-30 after a certain law was changed using a Cox hazard model using SPSS version 22. I want unadjusted results, but then want to enter covariates such as whether or not they are on medications, gender, and ... | g64451 | [
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0.014124601148068905,
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0.06893765926361084,
-... |
<p>I have run a stepwise regression on R. However, the summary of the final model includes some factors that are not significant. Why have these factors not been removed? Should I remove these from my model? The VIFs of these factors are all under 5.</p> | g49696 | [
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... |
<p>I read the great book Foundations of Statistical Natural Language Processing.
by Christopher D. Manning and Hinrich Schütze.</p>
<p>My question is regarding counting the number of ngrams for a given vocabulary.</p>
<p>For example, in the book, the given vocabulary has a size of 20000 words and the number of ngrams... | g64452 | [
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0.04738292843103409,
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0.007498187944293022,
0.0... |
<p>Is there a measure in logistic regression that maybe penalizes you for having too many independent variables like in multiple regression with the adjusted R squared?</p>
<p>That is, does having too many independent variables in a logistic regression hurt the model?</p>
<p>What about dummy variables? Can you have t... | g64453 | [
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0.02053752727806568,
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... |
<p>I have data collected from an experiment organized as follows:</p>
<p>Two sites, each with 30 trees. 15 are treated, 15 are control at each site. From each tree, we sample three pieces of the stem, and three pieces of the roots, so 6 level 1 samples per tree which is represented by one of two factor levels (root, s... | g64454 | [
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0.015643101185560226,
0.004111065529286861,
0.024472469463944435,
... |
<p>I am planning to do research on micro-finance institutes in India. Due to my limited knowledge on questionnaires I am facing challenges as to what kind of questions should be asked (Dichotomous, Likert scale) so that T- test, Anova , chi square or such parametric test can be implemented. Any help or sample questions... | g64455 | [
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0.022565072402358055,
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0.019805673509836197,
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-... |
<p>I want to develop a prediction model (Cox PH) for all-cause mortality in a dataset of participants of whom (almost) all have died at the end of follow-up (e.g. 1-year).</p>
<p>Instead of predicting the absolute risk of dying at a certain timepoint, I would like to predict the survival time (in months) for each ind... | g64456 | [
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0.005198577884584665,
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-0... |
<p>I asked this question at Mathoverflow but they recommend me to ask here. I need to find factored joint distribution of <a href="http://www.cs.huji.ac.il/~nir/Abstracts/FrGG1.html" rel="nofollow">Tree Augmented Naive Bayes</a> algorithm. I read the paper but I couldn't figure out the answer. Any help or pointers appr... | g64457 | [
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0.028194485232234,
0.04... |
<p>I had been using the term "Heywood Case" somewhat informally to refer to situations where an online, 'finite response' iteratively updated estimate of the variance became negative due to numerical precision issues. (I am using a variant of Welford's method to add data and to remove older data.) I was under the impr... | g37736 | [
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0.04226506128907204,
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0.019705409184098244,
0... |
<p>I've got a large set of data (20,000 data points), from which I want to take repeated samples of 10 data points. However, once I've picked those 10 data points, I want them to not be picked again.</p>
<p>I've tried using the <code>sample</code> function, but it doesn't seem to have an option to sample without repla... | g38198 | [
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0.029041824862360954,
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0.... |
<p>I am not that familiar with the analysis of time series data. However, I have what I think is a simple prediction task to address.</p>
<p>I have about five years of data from a common generating process. Each year represents a monotonically increasing function with a non-linear component. I have counts for each ... | g64458 | [
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0.005570058710873127,
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0.... |
<p>I'm sure I've come across a function like this in an R package before, but after extensive Googling I can't seem to find it anywhere. The function I'm thinking of produced a graphical summary for a variable given to it, producing output with some graphs (a histogram and perhaps a box and whisker plot) and some text ... | g42139 | [
0.01989559456706047,
0.002616853453218937,
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0.0266166552901268,
0.07469657808542252,
0.06197592243552208,
0.018492... |
<p>On <a href="http://en.wikipedia.org/wiki/Fisher_transformation" rel="nofollow">wiki page about Fisher transformation</a> I read that variance of sample correlation coefficient becomes smaller as population correlation coefficient (in absolute value) gets closer to 1. Could anybody, please explain why this happens? T... | g64459 | [
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0.037783876061439514,
0.0254896841943264,
0.0223... |
<p>Nowaday, there are lots of online courses related to machine learning, and there are lots of programming languages which can be used to do data mining, such as R, Python or Matlab. For example there are lots of data science related courses on coursera, some use R and some use Matlab. </p>
<p>Lots of the time I jus... | g64460 | [
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0.00717185391113162,
0.11608714610338211,
0.0123... |
<p>The sales history for customer A looks like this:</p>
<pre><code>Jan : $500 (4 sales)
Feb : $200 (2 sales)
Mar : $0 (0 sales)
</code></pre>
<p>etc..</p>
<p>I want to know:</p>
<ol>
<li>The probability of customer A having a sale occurring in a month.</li>
<li>Can we do anything interesting as far as taking int... | g22580 | [
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0.07724656164646149,
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0.0311904214322567,
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0.08385452628135681,
0.0275... |
<p>I'm having the following problem estimating something in GMM in R. I have created a "Hello World" below. In principle, I would not need GMM to estimate the parameters, but I want to use it to obtain standard errors as in my application there is likely time series dependence (there is not in the example below). Th... | g64461 | [
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0.08782283216714859,
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0.062461934983730316,
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0.022346092388033867,
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... |
<p>I am trying to regress a Ratio variable,Y, on an independent variable,X;
Variable X is endogenous, so I have to use an Instrumental Variable, Z;
both X and Z are continues variables.
How can I run this model in SAS. I know proc SYSLIN easily does it if the dependent variable is continues, but what if the dependent ... | g22581 | [
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0.012941545806825161,
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... |
<p>I've been reading about kernel methods, where you map original $N$ data points to a feature spaces, compute the kernel or gram matrix and plug that matrix into a standard, linear algorithm. This all sounds good when the feature space is infinite dimensional or otherwise very high-dimensional (much much larger than $... | g22582 | [
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0.006608151365071535,
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0.05012064799666405,
0.0250... |
<p>I'm reading Schaum's outline of probability, random var. and random processes.</p>
<p>In the second chapter they make it clear that a random variable $X$ is not a variable in the traditional sense but rather a function $X(\zeta)$ where $\zeta$ is a sample point in sample space $S$. So $S$ is the domain of r.v. $X$ ... | g64462 | [
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0.05283740535378456,
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0.044... |
<p>I have what I believe are an interesting QQ plot of the residuals of some sports data fitted using Poisson regression. My model is actually a live model to predict the number of remaining events in the game (basketball, soccer etc) from a set of explanatory variables. It looks also very much like the data is Poisson... | g64463 | [
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0.044130973517894745,
-0.013963689096271992,
-0.0342339426279068,
-0.06394560635089874,
-0.010172715410590172,
0.008055144920945168,
0.002710464410483837,
-0.032023657113313675,
-0... |
<p>I am a new entry in statistical field with lots of interest in this area. I would like to know any statistical book which can enhance my statistical knowledge meaning; wish to know the name of the book which can help me in model prediction....for eg. detailed explanation and steps of regression (incl multiple, logis... | g22587 | [
0.05237463116645813,
0.017314288765192032,
0.010464134626090527,
0.01516986358910799,
0.009283791296184063,
-0.016444014385342598,
0.01822316087782383,
0.01841842383146286,
-0.0048665814101696014,
-0.0023377984762191772,
0.01774074323475361,
-0.005950969643890858,
0.05052847042679787,
-0.0... |
<p>my time series is obviously periodic, but the seasonal decomposition using stl() is not working in R:</p>
<pre><code>a <- c(6.7, 20.3, 23.5, 7.9, 3.3, 2.0, 2.5, 2.9, 2.3, 5.0, 15.0, 20.1, 27.0, 28.2, 18.3, 7.8, 1.6, 0.8, 1.3, 1.2, 0.6,
1.6, 4.9, 24.2, 28.8, 23.6, 18.6, 5.3, 1.8, 0.4, 0.5, 0.2,... | g22589 | [
0.03420265391469002,
-0.03967611864209175,
0.021664530038833618,
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-0.030238578096032143,
-0.04554712772369385,
0.0899418294429779,
0.01799069531261921,
-0.003575267968699336,
0.022669164463877678,
0.013122773729264736,
0.03270995244383812,
0.011231428943574429,
0.0123... |
<p>What I want is to calculate the probability of a minimum number of rolls with a minimum value for at given number of dice, e.g. "if I roll 20 dice, what is the probability of getting at least 3 dice with a value of 5 or more?"</p>
<p>I have a brute force setup, that creates the Cartesian product and just enumerates... | g64464 | [
-0.013005723245441914,
0.06197670102119446,
0.008846910670399666,
-0.039708513766527176,
-0.01973291113972664,
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-0.013798068277537823,
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-0.05994008854031563,
-0.02322395145893097,
0.006641691084951162,
0.0756615698337555,
0.... |
<p>Suppose that $X_1,...,X_n$ are i.i.d. data from a $N(\mu, 100)$ distribution. I am trying to find the rejection region for the likelihood ratio test for level $\alpha= 0.10$ of the test:</p>
<p>$H_0: \mu = 0$ versus $H_1: \mu= 1.5$</p>
<p>Finally, if $n = 25$, I would like to find the power of the test.</p>
<p>W... | g64465 | [
0.01746436208486557,
0.001664135605096817,
-0.04234705865383148,
-0.06903813034296036,
-0.05200827494263649,
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0.037131574004888535,
0.05670810863375664,
-0.04578668624162674,
0.001024718745611608,
-0.03290436044335365,
0.041546620428562164,
-0.008132105693221092,
0.0... |
<p>I have two time series: (1) daily mean water temperature from 1988 to 2014 and (2) daily mean air temperature from 1968 to 2010. The water temperature time series has missing data, occurring on individual days and for periods of consecutive days (e.g., data for all of 1993 is missing). The air temperature data has d... | g64466 | [
0.027336090803146362,
-0.045777302235364914,
0.008746019564568996,
-0.018532954156398773,
-0.04846169799566269,
0.08381227403879166,
0.03233867511153221,
-0.008297890424728394,
-0.04671888053417206,
-0.007122647948563099,
0.02380095236003399,
0.028843678534030914,
0.051884815096855164,
0.0... |
<p>I have a system whose output I am analyzing. I've used a very simple hypothesis test with great results and now am curious <em>why</em> did I get such great results -- did I perhaps stumble on some kind of an "optimal" test without much formal statistics training?</p>
<p>My system can be in two states. When it's ... | g64467 | [
0.007123258430510759,
0.0194606501609087,
-0.007171837612986565,
-0.008740724064409733,
-0.022387556731700897,
-0.04285088926553726,
0.04669416695833206,
0.07145249843597412,
-0.018458468839526176,
-0.06679823249578476,
-0.027944814413785934,
0.02526271715760231,
0.0393855981528759,
0.0379... |
<p>Here is my problem. I am looking at various time series curves. Let's call them total spend aggregated over all customers on various products versus time. At any given time, I want to predict the spend on any product for which I don't have data, based on the spends from the products for which I do have data. The num... | g22591 | [
0.05145781859755516,
-0.0147715387865901,
-0.01236818078905344,
0.02275177091360092,
-0.047149159014225006,
-0.04415593668818474,
0.052098002284765244,
-0.013510484248399734,
0.028506293892860413,
0.021180089563131332,
-0.022947847843170166,
-0.0004892194410786033,
0.07069478929042816,
-0.... |
<p>I have a dataset which contains missing values, and I'm using imputation packages (<code>R</code>s <code>mi</code> and <code>mice</code>) to fill the missing values. I'd like to measure their performance on my data set, which may look like this (my actual data has more rows, but this example should serve just fine):... | g11860 | [
0.0408841110765934,
-0.0640232264995575,
-0.017248785123229027,
-0.04037430137395859,
0.0055946665816009045,
0.003703999798744917,
0.07021259516477585,
0.015226524323225021,
-0.03720023110508919,
0.04749221354722977,
0.0051080915145576,
0.0547708161175251,
-0.004603865556418896,
0.04174782... |
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